Binding of FKBP23 to BiP in ER Shown by Gel Filtration Chromatography
Chen Chen
a, Hui Ma
a, Ying Wang
a, and Huaifeng Mi
a,b,*
a Biochemical Section of Key Laboratory of Functional Polymer Materials,
Ministry of Education of China, Institute of Polymer Chemistry, Nankai University, 300071 Tianjin, China. Fax: (+86) 22 23 50 27 49. E-mail: hfmi@nankai.edu.cn
b Medical School of Nankai University, 300071 Tianjin, China
* Author for correspondence and reprint requests
Z. Naturforsch.62 c, 133Ð137 (2007); received July 24/August 31, 2006
FKBP23 was found in mouse endoplasmic reticulum (ER) in 1998. It consists of an N-terminal peptidyl-prolyl cis/trans isomerase (PPIase) domain and a C-terminal domain with Ca2+binding sites. Previously, we reported that FKBP23 specifically binds to BiP, the main protein of the molecular chaperone Hsp70 in ER lumen, and the binding is interrelated with the Ca2+ concentration. In this work we have found the existence of the complex FKBP23/BiP by separation of an ER extract using gel filtration chromatography (GFC), and that the existence of this complex is Ca2+-interrelated. This result further verified the Ca2+- interrelated binding of these two proteinsin vivo.
Key words:FKBP23, BiP, Gel Filtration Chromatography